A U.S. sailor at the Pearl Harbor Naval Shipyard in Hawaii fatally shot two Department of Defense civilian employees Wednesday and injured another before killing himself, military officials said.
The civilian shipyard worker who was injured is now in a stable condition at a local hospital, officials said.
"We have no indication yet whether they were targeted or if it was a random shooting," Rear Admiral Robert Chadwick said.
The shooting took place Wednesday afternoon at Dry Dock 2 of the shipyard which is located at Joint Base Pearl Harbor-Hickam. The identity of the gunman, tentatively identified as an active duty sailor assigned to the USS Columbia submarine, was not released.
Joint Base Pearl Harbor-Hickam said on Twitter that its security forces responded to the shooting, which prompted a lockdown of the base on the southern shore of Oahu. "The incident occurred at approximately 2:30 p.m.," Hawaii Standard Time, the tweet said. "Due to the ongoing security incident, access/gates to #JBPHH are closed." The base was later secured and the lockdown lifted, officials said.
NBC affiliate KHNL reported that the public address system urged people to take cover during the shooting.
One witness interviewed by KHNL said that he was at his desk and heard pops and recognized that as gunshots, and that he looked out the window and saw three people on the ground.
At least two of the victims were hospitalized. The Queen's Medical Center and Pali Momi Medical Center each told NBC News that it had a victim from the shooting but did not provide further details.
Hawaii Governor David Ige tweeted that the White House had reached out to offer assistance from federal agencies.
"The President has been briefed on the shooting at Joint Base Pearl Harbor-Hickam in Hawaii and continues to monitor the situation," White House deputy press secretary Hogan Gidley said.
Democratic presidential candidate Rep. Tulsi Gabbard of Hawaii also tweeted her support for the victims, saying: "Sending my aloha and well wishes to the victims of today's shooting at Pearl Harbor Naval Shipyard. Our gratitude goes out to the first responders who took action to secure the base and keep people safe."
The shooting is currently under investigation by base security and the U.S. Navy. The names of the victims will not be released until their next of kin have been notified, officials said.
"Our thoughts are with the families of the victims and everyone involved. I can say that we are mobilizing support services for naval shipyard personnel as well as everyone else who may be affected by this tragic event," Chadwick said.
The shooting took place just three days before the 78th anniversary of the Dec. 7, 1941 Japanese attack on Pearl Harbor.
NBC News contributed to this report.